A conventional positive photosensitive resin composition is generally prepared by mixing a resin with a phenol-type hydroxy group easily dissolved in an alkali aqueous solution and a photosensitizer suppressing dissolution of the resin during non-exposure and promoting development of the resin or suspending the suppression of dissolution of the resin during exposure, thus making patterning of the resin possible. The resin may include a novolac resin prepared by condensation-polymerizing a phenol-based compound and formaldehyde and a poly(4-hydroxy)styrene resin, polyhydroxy amide as a polybenzoxazole precursor, and the like. The photosensitizer may include a diazonaphthoquinone compound including sulfonic acid ester and amide at the 4- or 5-position.
The positive photosensitive resin composition may have dissolution-suppressing performance depending on capability of a photosensitizer suppressing dissolution of a non-exposed part, capability of the photosensitizer easily dissolved after the exposure, and capability of recovering or promoting a dissolution rate of the resin due to the dissolution. A conventional diazonaphthoquinone compound may have excellent photodissolution rate and light absorption but not good capability of inhibiting dissolution of a non-exposed part. Accordingly, typical compositions include increased amounts of diazonaphthoquinone compound to secure an appropriate residual film ratio for patterning. The increased amount of diazonaphthoquinone compound is dissolved to pattern an exposed part, which can require a higher exposure dose and resulting relatively low sensitivity.
Therefore, there is a need for a photosensitive assistant which can inhibit dissolution of a non-exposed part.